As the climate changes, conservationists are divided over the most effective way to preserve animal and plant diversity because they cannot simply preserve the status quo. Ensuring species can shift to track the climate to which they are suited is a complex problem, especially when there are competing demands on land use. A simple prediction is that more habitat would help species to shift, but it is not obvious what the best spatial locations for habitat would be.

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A new study led by scientists at the University of York says that well placed habitat "stepping stones" would lead to faster range expansion than the equivalent amount and quality of habitat tacked onto existing sites. The result applies to situations where a species will have to cross gaps of several times the distance one individual can normally traverse, i.e. to species whose habitat is fairly rare.

This will be relevant to numerous species that are already threatened for reasons other than climate change, and have very little habitat available. For example, the most important wildlife sites in Europe (called the Natura 2000 sites) make up 18 per cent of the land area, and the habitat for any one priority species will be much less than that.

The study, which is published in PLOS ONE, involved researchers from the Universities of York, Leeds and Aberdeen.

Lead author Dr Jenny Hodgson, of the Department of Biology at York, said: "Species in these fragmented habitats would need to make a series of "leapfrogging" moves over multiple generations to colonise new landscapes. Our research offers a way to identify existing chains of habitat patches that can enable this leapfrogging, but that may not seem obviously connected when looking at a map. When no suitable chains exist, the method can also help to plan new habitat stepping stones in the gaps that will be most difficult to cross."